@mic :
seeing a 256b intro at 2fps under dosbox have never been exciting... (maybe its ok for some people with recent core2duo)

most 256b require lot of power. some require so much that even not emulated they are still fucking slow...

i think the problem came from dosbox itself.. if com file is already compiled(instead of being interpreted each time) and interupts, I/O replaced by proper emulated functions, there is not reason an intro should run 10x slower than on real hardware.... (like it is on dosbox)

and why i cannot run 256b??? simple : i get a recent nvidia card where int 10h function have been removed and so cannot display most 256b (even in dos, linux or whatever)

thats why i'm very happy when a 256b come with an SDL version but i understand a sdl version cannot always be easily done...